shell.pl

$OUTPUT_AUTOFLUSH = 1; # this thing turns off buffering between newlines

while (1) {
  print "perl% ";
  my $command = <STDIN>;  	# get some user input
  last if $command eq ''; 	# exit the loop
  chomp $command; 		# remove newline from our input
  my ($program, @args) = split /\s+/, $command;
  my $pid = fork;
  if (! defined $pid) { print STDERR "Couldn't fork: $!\n" }
  elsif ($pid != 0) { wait } 	# I am the parent
  else { exec $program, @args;  # I am the child
	 die "Couldn't exec: $!\n"; 
	}
}